Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/04—Cleaning involving contact with liquid
  • B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
  • C11D7/02—Inorganic compounds
  • C11D7/04—Water-soluble compounds
  • C11D7/06—Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/10—Objects to be cleaned
  • C11D2111/14—Hard surfaces
  • C11D2111/20—Industrial or commercial equipment, e.g. reactors, tubes or engines
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D2111/00—Cleaning compositions characterised by the objects to be cleaned; Cleaning compositions characterised by non-standard cleaning or washing processes
  • C11D2111/40—Specific cleaning or washing processes
  • C11D2111/44—Multi-step processes

Definitions

• the invention relates to a method for cleaning plant parts, which for Production or processing of (meth) acrylic acid esters can be used.
• (meth) acrylic acid esters are generally produced by esterification of (Meth) acrylic acid with alkanols in the presence of strong acids and optionally an entrainer to remove the esterification water manufactured.
• the synthesis is preferably carried out in stirred reactors with attached Distillation columns, working up with the help of several Distillation columns and extraction equipment (see Kirk Othmer, Encyclopedia of Chemical Technology, 4th Ed., Vol. 1, pages 301-302).
• the Heat supply and cooling are usually carried out with heat exchangers, such as plate, tube bundle, spiral heat exchangers or circulation evaporators.
• the distillation columns are equipped with internals such as sieve, bell and dual flow trays or directed packs or contain packing.
• a major problem in the production of (meth) acrylic acid esters is the large one Tendency of the (meth) acrylic acid compounds for radical polymerization, especially under the influence of heat or light.
• Tendency of the (meth) acrylic acid compounds for radical polymerization especially under the influence of heat or light.
• Are esterification in order to achieve economical esterification rates usually reaction temperatures of 80 to 140 ° C necessary.
• In the Cleaning requires the necessary separation of the light and distillative High boilers and the isolation of the target ester temperatures from 60 to 150 ° C.
• the esters are exposed to temperature loads that are easily a can trigger unwanted polymerization.
• the pollution of the Manufacturing equipment, the distillation columns and the clogging of the lines, Pumps, evaporators ("fouling") and condensers through polymers mostly the result.
• Acrylic acid which still contains various carbonyl compounds, such as formaldehyde, Acetaldehyde, furfural, benzaldehyde, protoanemonin and dicarboxylic acids, such as Contains maleic acid or itaconic acid, there is increased pollution and Clogging of system parts.
• carbonyl compounds such as formaldehyde, Acetaldehyde, furfural, benzaldehyde, protoanemonin and dicarboxylic acids, such as Contains maleic acid or itaconic acid
• the cleaning of the systems for example by treatment with solvents or by manual removal of the polymer is a complex, expensive and environmentally harmful process.
• the parts of the system are cleaned usually by treatment with suitable organic solvents, for Example dimethyl, dibutylformamide, acetamide, sulfolane or N-methylpyrrolidone.
• suitable organic solvents for Example dimethyl, dibutylformamide, acetamide, sulfolane or N-methylpyrrolidone.
• suitable organic solvents for Example dimethyl, dibutylformamide, acetamide, sulfolane or N-methylpyrrolidone.
• the resulting solutions have to be disposed of at great expense.
• manual removal of the polymer for example distillation trays or evaporator tubes.
• the object of the present invention is to provide a method for Cleaning of plant parts that are used to manufacture or process (Meth) acrylic acid esters are used, which have the above disadvantages avoids.
• the system parts Before rinsing with alkali hydroxide solution, the system parts are made as possible completely emptied, so that only the smallest possible amount of reaction mixture or remain on any substance present in the plant part.
• the concentration of the alkali hydroxide solution used is preferably 10 up to 30 wt .-%, based on the weight of the finished solution.
• the temperature of the alkali hydroxide solution during rinsing is preferably 20 up to 140 ° C, particularly preferably 60 to 100 ° C. It should be ensured that the alkali hydroxide solution this temperature on contact with the deposited Has polymers in the plant parts. If the entire plant on the heated appropriate temperature, the temperature corresponds to the one used Alkali hydroxide solution of this desired temperature. Plant parts are not heated to this temperature, so the temperature of the used Alkali hydroxide solution are adjusted so that at the points with Polymer coating the specified temperature prevails. If necessary, the The temperature of the alkali hydroxide solution when it is introduced into the system accordingly chosen higher.
• Sodium hydroxide is preferably used as the alkali hydroxide.
• the Alkali hydroxide solution can be circulated through the corresponding parts of the system be driven to achieve a sufficiently long treatment period.
• the Treatment duration is depending on the degree of deposits in the Plant parts usually 1 to 24 hours.
• the duration of treatment that Concentration of the alkali hydroxide solution and the temperature depend on the Type of (meth) acrylic acid ester used in the plant section and the type and Amount of polymer.
• (meth) acrylic acid esters are made Alcohols, such as alkanols with 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms produced by direct esterification or transesterification.
• examples for Alkanols are methanol, ethanol, n-butanol, 2-ethylhexanol, dimethylaminoethanol.
• the (meth) acrylic acid esters can also be obtained by reacting olefins, preferably isobutene, can be obtained with (meth) acrylic acid.
• the parts of the system to be cleaned are those parts of the system that are compatible with the Raw materials or products in the manufacture or processing of (Meth) acrylic acid esters, especially in the esterification of (meth) acrylic acid come into contact with alkanols. It can happen with the system parts for example around reactors, possibly connected to form a unit, Distillation columns, extraction equipment, heat exchangers, evaporators, Act capacitors, lines or pumps. It is preferably in the connected plant parts by a distillation unit, the one Has flushing line between the evaporator and the top of the column. In these Plant parts are stored especially in the manufacture and processing of Polymers formed from (meth) acrylic acid esters.
• Treatment with the Alkali hydroxide solution at least partially saponifies the ester groups the (meth) acrylic acid ester polymers so that it releases the Alkanol component comes.
• the polymer of the parts of the system are detached and go into solution in whole or in part and so can are discharged from the system parts with the alkali hydroxide solution.
• distillation facilities can be cleaned well with the alkali hydroxide solution are preferably equipped with their own flushing lines. This allow the transport of the alkali hydroxide solution, for example in The column evaporator is heated to the top of the column.
• the flush lines allow the column top and all column trays to be treated with the Alkali hydroxide.
• the alcohols formed during cleaning, in particular alkanols, are preferably after removal with the alkali hydroxide solution from the Plant parts in step (c) by phase separation, distillation or stripping separated from the alkali hydroxide solution in which they are contained.
• the educated If its water solubility is low, alkanol forms a second phase, the can be easily separated from the alkali hydroxide solution. It is about a water-soluble alkanol, this is preferably by distillation or by Stripping with a stripping gas such as air or water vapor.
• the Distillation separation and stripping can, for example, in one heatable stirred reactor with an attached column.
• the Energy input can be done in a known manner, for example by double wall heating, Pipe coils or circulating water heaters take place.
• the stripping of the alkanol can be carried out in a stripping column in a known manner. For example, preferably hot, alkali hydroxide solution after rinsing at the top of the column be fed in and stripped in countercurrent with air or steam.
• the condensation of the distillate or the alkanol from the stripping gas can with known cooling devices, such as tube bundles or Plate heat exchangers are made.
• the stripping preferably takes place in the stripping unit, which is generally in each Plant for the production of (meth) acrylic acid esters is present and in the alkanol-containing wastewater that is usually produced is stripped.
• the alcohol, especially the alkanol can be directly after the separation in the Esterification reaction are recycled.
• the alkali hydroxide solution after cleaning collected and used several times for cleaning.
• the Concentration of alkali hydroxide but preferably not less than 5% by weight decrease in order not to deteriorate the cleaning performance.
• the method according to the invention can be carried out simply and quickly, as a result the plant availability is increased. In addition, the recovery of Valuable products, especially alkanols possible.
• a dual flow column was used as the distillation column for the distillation of reaction mixtures, which is obtained in the esterification of (meth) acrylic acid with alkanols.
• the distillation process was interrupted and the distillation unit emptied.
• the corresponding evaporator was then filled with 20% by weight aqueous NaOH solution.
• the NaOH solution was heated to a temperature of 80 ° C. and applied to the top of the column via a flushing line. After a treatment period of 5 hours with this hot solution at a pumping rate of about 10 m 3 / h, it was pumped into a storage container and the distillation unit was rinsed with water and, if necessary, dried with air.
• a rinsing solution resulting from the cleaning of a plant for the production of butyl acrylate which contained about 7% by weight of NaOH and about 5% by weight of butanol, was placed at a temperature of 60 ° C. on the top of a stripping column, the 30 dual flow Floors, brought and stripped in countercurrent with steam (0.2 t / m 3 ).
• the condensate obtained disintegrated into two phases, the aqueous phase being applied again to the top of the column.
• the organic phase, the butanol was fed directly to the esterification. About 90% of the butanol was recovered.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Detergent Compositions (AREA)
• Cleaning By Liquid Or Steam (AREA)

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Publications (2)

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• 1997
  • 1997-10-22 DE DE19746688A patent/DE19746688A1/de not_active Withdrawn
• 1998
  • 1998-10-21 US US09/509,817 patent/US6568406B2/en not_active Expired - Lifetime
  • 1998-10-21 JP JP2000516939A patent/JP4248140B2/ja not_active Expired - Lifetime
  • 1998-10-21 TW TW087117390A patent/TW553779B/zh not_active IP Right Cessation
  • 1998-10-21 KR KR20007004280A patent/KR100579677B1/ko not_active IP Right Cessation
  • 1998-10-21 DE DE59807142T patent/DE59807142D1/de not_active Expired - Lifetime
  • 1998-10-21 CZ CZ20001458A patent/CZ297843B6/cs not_active IP Right Cessation
  • 1998-10-21 EP EP98955504A patent/EP1042271B1/de not_active Expired - Lifetime
  • 1998-10-21 ID IDW20000704A patent/ID23871A/id unknown
  • 1998-10-21 BR BR9813106-0A patent/BR9813106A/pt not_active Application Discontinuation
  • 1998-10-21 AU AU12308/99A patent/AU1230899A/en not_active Abandoned
  • 1998-10-21 CN CN98809880A patent/CN1113848C/zh not_active Expired - Lifetime
  • 1998-10-21 WO PCT/EP1998/006677 patent/WO1999020595A1/de active IP Right Grant
  • 1998-10-22 MY MYPI98004822A patent/MY120165A/en unknown
• 2000
  • 2000-03-03 MX MXPA00002230 patent/MX217992B/es unknown

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